computer won't boot

this is a very perculiar issue i'm having, i recently upgraded the mobo and cpu on my desktop(1 gb ram, amd 64 4000+, asrock dual-mobo and a evga 5500+), and now that i've installed everything, nothing will boot. i can get into my bios settings, it gets past the post and all that but the issue comes up when i try to boot an os.
i've tried booting from a live linux cd, it got past the initial loading of files then crashed, same thing when i try to install windows xp.
naturally, i tried to boot from a floppy, but the flopy drive won't work, the light just stays on regardless of whick way i plug in the cable.
my computer does recognise the harddrive and the cd drive, and i'm suspecting that either my mobo has a short or my cpu shorted out.

Go back to barebones [CPU, RAM, Onboard A/V, power, 1 stick of ram...] and start your troubleshooting from there. take teh mobo out of the case onto a non-conductive surface to test if it is shorting or not.

I can't seem to figure out how to post a new thread on here, so basicly here is my problem. I have an Alienware - Aurora, and when I tried to turn it on last night, it gave me a black screen that said Searching, then BIOS not installed, then Program not found. I called Alienware, they made me pay $199 for a 2 year warranty renewal, just to tell me I am going to have to send my computer in for a new motherboard, that even though I JUST got a new mother board in May 2005, the warranty for that only lasts 12 months, and we are past that, so now they want me to pay another $600 for parts and labor. I talked to a few friends of mine who know alittle about computers, and they said if it was the motherboard, my computer wouldn't start at all. I did a couple google searches and thats how I came across this website, from a couple threads I have read, maybe I just need to remove the battery for a few minutes? I attempted to start my computer again this morning, and that time is started all the way, then froze when loading my desktop icons, and went into blue screen saying there was an error and to restart. Someone please help!!